(i) Technical Field
The present invention relates to imaging devices and focal plane shutters.
(ii) Related Art
Japanese Utility Model No. 3176166 discloses a focal plane shutter that includes a leading shutter actuator and a trailing shutter actuator respectively driving a leading shutter and a trailing shutter.
The energization of the actuator increases the heat generation amount of a coil of the actuator to increase its temperature. This results in an increase in a resistance value of the coil, which delays rise of a drive current value.
Thus, for example, in a case of a large difference in the energization period, in the coil resistance value, in the applied current value, in the applied voltage value, or the like between the leading shutter actuator and the trailing shutter actuator, a difference between both actuators in the heat generation amount is also increased. Thus, the continuous use also increases a difference in the temperature between the coils of the leading shutter actuator and the trailing shutter actuator. This increases a difference in the rotational speed between the leading shutter actuator and the trailing shutter actuator, which leads to a large difference between in the moving speed between the leading shutter and the trailing shutter. This might influence image quality.